General Motors Tech Chevy tech talk within.

Low oil pressure at hot idle

  #1  
Old 02-26-2012, 08:36 PM
Beginner
Thread Starter
Join Date: Feb 2012
Posts: 1
Default Low oil pressure at hot idle

I have a 1997 gmc Sierra 1500 5.7 motor with 112,000 miles. I have low oil pressure at hot idle...I put a new sending unit and it didn't fix it. I put a manual gauge on it and it still shows low. I put a new oil pump and all new bearings on the crank shaft. When motor is cold I have 60 psi and when the motor warms up it gradually goes down...when drivin the truck after its warm it runs between 15 and 20 psi and at idle it's at 0 psi and the check gauges light comes on. I Need help on what to do next..
 
  #2  
Old 03-11-2012, 03:50 AM
Beginner
Join Date: Mar 2012
Posts: 1
Smile heated hose

  #3  
Old 03-14-2012, 08:49 PM
Beginner
Join Date: Mar 2012
Posts: 3
Default

Was there any change at all when the oil pump and bearings were changed?

If you had no change after the new parts went in then I would wonder about the cam bearings. The don't usually wear much but if they were worn you would lose pressure when things got hot. Cracks at various points could cause it too.

Other than that
Were all clearances checked on the oil pump and rod/main bearings? What type of oil are you using? Was assembly lube used (vs oil) on the rebuild? Was the oil system primed before first startup? Did this come on suddenly or slowly over time?

I know, more questions than answers but more detail might help. I am rebuilding my engine now because of the same problem. In my case obviously worn bearings.
 
  #4  
Old 03-30-2012, 11:56 AM
Diesel Dan's Avatar
Senior Member
Join Date: Mar 2012
Location: Warren, Ohio
Posts: 190
Default

Were the old bearings showing wear or excessive clearance?
If so your cam bearings are bad as well.
Cheapest fix would be a high volume std pressure oil pump. Might produce enough volume at idle but won't fix the root cause.
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
robin623
Ford F-150 Forum
1
11-27-2012 11:12 PM
ofg
Chevy Silverado/ GMC Sierra Forum
4
03-27-2012 06:53 AM
ElectroJoe
General Motors Tech
1
08-22-2011 03:21 PM
korygrandy
Chevy Silverado/ GMC Sierra Forum
2
07-29-2010 11:52 PM
mikeysride9812
Chevy Silverado/ GMC Sierra Forum
2
11-16-2007 04:48 AM


Thread Tools
Search this Thread
Quick Reply: Low oil pressure at hot idle


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.